diff options
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index 306fb7e199..d867414a98 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -18503,6 +18503,20 @@ static SDValue PerformAndCombine(SDNode *N, SelectionDAG &DAG, } } // BEXTR + // Check for BZHI with contiguous mask: (and X, 0x0..0f..f) + // This should be checked after BEXTR - when X is a shift, a BEXTR is + // preferrable. + if (Subtarget->hasBMI2()) { + if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N1)) { + uint64_t Mask = C->getZExtValue(); + if (isMask_64(Mask)) { + unsigned LZ = CountTrailingOnes_64(Mask); + return DAG.getNode(X86ISD::BZHI, DL, VT, N0, + DAG.getConstant(LZ, MVT::i8)); + } + } + } + return SDValue(); } |